1. Field of the Invention
The present invention relates to a new and improved furnace, a burner and a method for burning pulverized coal in a highly efficient and controlled manner to reduce and minimize the formation of oxides of nitrogen and other pollutants in the burning process. The present invention is an improvement of the burner and method of co-pending U.S. patent applications Ser. Nos. 469,019 and 469,117, filed Feb. 23, 1983, and assigned to the same assignee as the present application. 2. Description of the Prior Art
Over the years a wide variety of burner and furnace designs have been developed for handling pulverized coal in burning the coal. One of the main concerns in firing pulverized coal and other fossil fuels is the unwanted production of oxides of nitrogen (known as NO.sub.x) in the combustion process.
A number of articles and reports have been published concerning oxides of nitrogen as pollutants and concerning burner and furnace designs. These articles and reports also deal with methods for reducing and controlling the formation of NO.sub.x and are listed as follows:
Itse, D. C. and Penterson C. A., "NO.sub.x Control Technology For Industrial Combustion Systems", The American Flame Research Committee Symposium On Combustion Diagnostics From Fuel Bunker To Stack, Oct. 5, 1983. PA0 Claypole, T. C., Syred, N., "The Effect of Swirl Burner Aerodynamics On NO.sub.x Formation", Eighteenth Symposium on Combustion, The Combustion Institute, 1981. PA0 Lisauskas, R. A., Rawdon, A. H., "Status of NO.sub.x Control for Riley Stoker Wall-Fired and TURBO Furnaces", EPA-EPRI Joint Symposium on Stationary Combustion NO.sub.x Control, 1982. PA0 Roberts, P. A., "Near Field Aerodynamics Research Program", International Flame Research Foundation, 1983. PA0 Rawdon, A. H., Johnson, S. A., "Application of NO.sub.x Control Technology to Power Boilers", 1973 American Power Conference. PA0 Lisauskas, R. A., Marshall J. J., "An Evaluation of NO.sub.x Emissions from Coal-fired Steam Generators", 1980 EPA/EPRI Joint Symposium on Stationary Combustion NO.sub.x Control. PA0 Lim, K. J., Milligan, R. J., Lips, H. I., Castaldini, C., Merrill, R. S. and Mason, H. B., "Technology Assessment Report for Industrial Boiler Applications: NO.sub.x Combustion Modification," Acurex Corporation for Environmental Protection Agency, EPA-600/7-79-178f, Research Triangle Park, N.C., December, 1979. PA0 Heap, M. P., Lowes, T. M., Walmsley, R., Bartelds, H. and LeVaguerese, P., "Burner Criteria for NO.sub.x Control, Volume 1, Influence of Burner Variables on NO.sub.x in Pulverized Coal Flames," International Flame Research Foundation, EPA-600/2-76-061a, March, 1976. PA0 Brown, R. A., Mason, H. B., Schreiber, R. J., "Systems Analysis Requirements for Nitrogen Oxide Control of Stationary Sources." NTIS-PB-237-367, EPA-650/2-74-091, September, 1974. PA0 Information presented at the Third Technical Panel Meeting, "EPA Low NO.sub.x Burner Technology and Fuels Characterization," Newport Beach, Calif., November, 1979. PA0 Beer, J. M., and Chigier, N. A., "Combustion Aerodynamics" Applied Science Publishers, 1972. PA0 DyKema, O. W., "Analysis of Test Data for NO.sub.x Control in Coal Fired Utility Boilers," Aerospace Corporation for Environmental Protection Agency, EPA 600/2-76-274 (NTIS No. PB 261 066,) Research Triangle Park, N.C., October, 1976. PA0 Martin, G. B. and Bowen J. S., "NO.sub.x Control Overview, International Symposium on NO.sub.x Reduction in Industrial Boilers, Heaters and Furnaces," Houston, Tex., Oct. 22-23, 1979. PA0 Rawdon, A. H. and Johnson, S. A. "Application of NO.sub.x Control Technology to Power Boilers," Proceedings of the American Power Conference, Vol. 35, pp. 828-837, 1973. PA0 Rawdon, A. H., Lisauskas, R. A., Zone, F. J., "Design and Operation of Coal-Fired Turbo R Furnaces for NO.sub.x Control," presented at the Second EPRI NO.sub.x Technology Seminar, Denver, Col., November, 1978. PA0 Brown, R. A., "Alternate Fuels and Low NO.sub.x Tangential Burner Development Program," proceedings of the Third Stationary Source Combustion Symposium Volume II, Advanced Processes and Special Topics, Acurex Corporation for Environmental Protection Agency, EPA-600/7-79-0506, Research Triangle Park, N.C., February 1979. PA0 Zeldovich, J., "Acta Physicochimica U.R.S.S.," Volume 21, No. 4, 577, 1946. PA0 Pershing, D. W., Brown, J. W., Martin, G. B. Berkau, E. E., "Influence of Design Variables on the Production of Thermal and Fuel NO.sub.x from Residual Oil and Coal Combustion," presented at the 66th Annual AICHe Meeting, Philadelphia, Pa., November, 1973. PA0 Penterson, C. A., "Development of an Economical Low NO.sub.x Firing System For Coal Fired Steam Generators, 1982 Joint Power Generation Conference, Denver, Col., Oct. 17-21, 1982.
In addition, the following U.S. patents are directed towards burners for furnaces and the like which employ pulverized coal or other hydrocarbon fossil fuel as a source of energy for combustion:
______________________________________ 246,321 Litchfield et al 3,150,710 Miller 1,073,463 Banes 3,250,236 Zelinski 1,342,135 Schmidt 3,283,801 Blodgett et al 1,779,647 Van Brunt 3,284,008 Miller 1,817,911 Andrews et al 3,401,675 Miller 1,953,090 Vroom 3,349,826 Poole et al 1,993,901 Silley 3,450,504 Korwin 2,046,767 Campbell 3,782,884 Shumaker 2,158,521 Nahigyan 3,788,797 Mayfield et al 2,190,190 Peterson 3,934,522 Booker 2,284,708 Woolley 4,019,851 Smith et al 2,325,318 Hendrix 4,050,879 Takahashi et al 2,823,628 Poole et al 4,089,682 Blackburn 3,007,084 Thomasian et al 4,147,116 Graybill 3,147,795 Livingston et al 4,157,889 Bonnel 4,228,747 Smirlock et al 4,206,712 Vatsky 4,221,558 Santisi 4,321,034 Taccone 4,333,405 Mitchelfelder et al ______________________________________